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                                                          - the "trinity" head -

 

 

 

 

 

how to do a state-of-the-art live recording

 

 


 

                                                            - Schöps CMC3 -

                                            original (above) and modified (below)

 


 

One of my biggest passions has long been, and still is, live recording of classical music. You cannot image the joy you are pervaded with, after making a beautiful recording of a musical event that is always unique, and the awareness that it will remain with you forever and ... after you as well!

I started in 1976 in Italy, recording unknown artists, and, year by year, I met and recorded many of the biggest Names in classical music (see the page "about Franco") and today, here in NZ, I keep on feeding my passion for live recording, being the official recorder for Bach Musica New Zealand (of which I have the honour to be a member of the Board of Directors), Auckland Chamber Orchestra, Aorangi Symphony Orchestra, Auckland Youth Orchestra, Jade String Quartet, Auckland Opera Studio and Hausmusik New Zealand. Here, I have also recorded several worldwide premieres of New Zealand contemporary composers of classical music (I love their music very much!).

From 1976 on, I have technically matured, in order to reach something very close to a reproduction of the reality. Nowadays, I’m at around 95% of the reality and I think that this is an almost impassable limit.

To achieve such a result, you need a perfect recording system and a perfect hi-fi system. This sentence is quite intriguing, because the recording and its reproduction are correlatives: I had to proceed by degrees, because you use the recording to improve the audio system and the audio system to improve the recording technique! It’s like trying to solve the conundrum of the egg and the chicken (which one was born first). Anyway, it took me a lot of time to achieve my current results, but in the end I was successful.

I remember the first time I made a recording (an organ concert) and the shock I had when, back home, I played it through the system! Until that moment, I was very happy about my system, but now I suddenly understood that there was something wrong; at first I blamed the recording, but later I realized that the fault was due 30% to the recording and 70% to the playback system.

Now, let me tell you about the equipment I used when I started: just a Revox A77 and two Sennheiser 441. The hi-fi system was made of a preamp AGI, a Michaelson & Austin TVA-1 (tube amp) and a pair of Dahlquist DQ10 (on stands 40 cm. high), connected by big, hand-made speaker cables (probably, I was the first “esoteric" hi-fi man in Italy). I assure you that my system, in the tragic era of the "dinosaurs" (Klipschorn, JBL, Altec Lansing, Magneplanar etc.), usually connected by a speaker cable made of a tiny red and black wire, was like a “green man” of Mars around the world! As already said, with LPs it sounded great, but with live recordings … So, I begun upgrading the recording system, buying two Schöps CMC3-MK41, a two track Revox A700 (inhumanly heavy, 25 kg.) and later (1978) upgraded the hi-fi system too, mainly with the addition of the just-arrived sub-woofer (unknown word at that time) B2-50 from audio pro, in order to have a reference in the infra-bass and a better and cleaner mid-high too (in the page "school of sound", I explain how this happens). Furthermore, it has been a tremendous gift to the tube amp as well, which, relieved of reproducing the bass and infra-bass range, became cleaner and faster. At the end of the day, the addition was miraculous and the whole system was brought to new life! It is interesting to let you know that after 38 years that sub is still in my house. It is an essential part of my main system and, considering the panorama of the "competitors" around, I have no intention of replacing it at all. These 38 years are the measure of the technological gap between audio pro and ... the rest!

In 1980 I sold the Dahlquist and the TVA-1 and upgraded to the active audio pro A4-14, incredible speakers which I enjoyed until 2003. Since then, the era of Sachem started and now my reference system is made by Sachem Pure, two Sachem mono-blocks, a Carat Peridot DAC (connected to my computer), a "modified" B2-50 sub and a pair of audio pro Avanti A.20 DC, connected by NORDOST 2-flat cable. Please note that the Avanti A.20 DC are centre speakers, but I have set them vertically on two (60cm) stands, in order to have a perfect D'Appolito configuration, which is the best solution to achieve a lovely image. This system, in my listening position, proudly sports a 20↔16kHz frequency response between ±3dB, with 20kHz at -6dB (as per the dictates of Bruel & Kjaer), a lightning dynamic and speed, perfect image and the lowest distortion possible nowadays, that means incredible clarity.

 


 

                                                                                                    - power supply and the three preamps on the background -

 

Even if I consider myself a “digital” man, I have to say that I made beautiful recordings with the Revox too, running it at 38 cm/sec, 2 tracks and using the very thick tape AMPEX 456. Employing this thick tape and setting up very high the BIAS of the A700, I reached the saturation point at +16dB. This is the "secret" to minimise the tape-hiss, which is the main nightmare of the analogue.

Anyway, on the night of 12/05/81, using a 14 bit Sharp AD/DA converter, just arrived from Germany, and a VHS video recorder, I recorded my dear friend Marco Taio (classical guitarist) performing a concert in Rho (Milan). For what I know, it was the very first digital live recording of a concert in Italy and, when I heard the result, I just said: "hi-fi has been born"!

In my opinion, even if there is not a single reason, you could still make analogue recordings of light music, but not of classical music. Getting totally rid of tape-hiss during an “adagio” was a dream come true, along with the increased clarity of the whole audio-band, but in particular the absolute precision and dynamic of the bass range. So, as soon as it arrived on the Italian market, I bought a Sony PCM F1 and years later a Tascam DAT (DA-30 MK II). I still have them!

Regarding the pathetic diatribe “analogue versus digital” recordings, a friend of mine told me that lately the hi-fi magazines have started again "bullshitting" about the superiority of analogue. This is the umpteenth confirmation that, when in 1987 I stopped reading hi-fi magazines (to prevent bilious attacks), I did the right thing! By the way, I take the liberty to strongly advise you to do the same, if you want to be “uncontaminated” and unbiased by the grotesque opinions and statements of pathetic reviewers, who are "officially" authorised to mislead you and freely play with a lot of your money too! Please, don't believe the inept guys who say the digital is "harsh": the only diversity is that the digital, differently to the analogue, doesn't forgive anything and mercilessly puts on a silver disc what comes from the mics, mixer and recording technique, that, in the industrial recordings, almost always is not the best possible (to use an euphemism). If you take the opportunity of listening to my recordings, you'll realise that the adjective "harsh" has to be used for different purposes!

After this short story of my recording life, now I tell you what I use nowadays and in how to make a state-of-the-art recording of a sonic event.

Starting with the recorder, I use a portable Tascam HD-P2, which is a great (small and light) professional machine.

Coming to the microphones, I employ only Schöps condenser mics. However, you have to know that, as all the other brands, Schöps produce a large variety of mics, for many different uses, and with different characteristics. After trying out the few that suited my needs, I opted for the MK41 capsules, which are super-cardioid, and feature the unique perquisite of being in phase at all frequencies: practically, they produce a very stable image, with localisation of the performers. If you set up two of them at 110°, with the capsules 17/18 cm. far apart, you reconstruct the physiognomy of two human ears, with a panoramic view of the aural scene in front of the mics! See above a shot of my "holy trinity", the virtual-head I made.

Anyway, for a couple of years I have used only this two MK41 (the third microphone arrived in 1980) and I assure you that, when you listen to the recording, you have a three-dimensional sound, with a perfect localization of the players, in direction and depth.

 


 

                                                                                     - power supply and back panel with output-sockets, transformer and AC filter -

 

But … there is always a “but”, and in this case the "but" is that the MK41 capsules, as all cardioid capsules, feature a 6dB/oct mechanical roll-off, starting from 200Hz, so the response at 20Hz is down around -12dB. This means that if you record a violin, a flute, a small Baroque ensemble or a flying bluebottle, the problem is "almost" inaudible, but if you do an organ, a bass-drum or a big orchestra, you start suffering! If you have booming floorstanding speakers, this problem is partially “self-mitigated” by the awful "hill" in the bass frequency response of these speakers, but, in case you have a serious system with a flat response in the bass-infrabass department (as is mine), you’ll get really frustrated!

Well, being a former bass-guitarist in a band and obsessed by the reproduction of a perfect bass range, I had to find a solution to this "sonic tragedy", so I thought of employing a different recording technique, featuring two Schöps MK2 (panoramic mics) with a separator disk: this technique is called OSS and you must use panoramic mics, which, in contrast to the cardioid ones, are totally flat down to 20Hz.

So, one night I recorded “I Solisti Veneti” with this system and, at the same time, with my normal system too. Later, comparing the two recordings (switching in real time), as much as I was enthusiastic about the bass range of the recording made by the OSS-MK2 technique, the rest of the audio band could not stand comparison with the one achievable with the MK41. So, since that night, my "microphone-obsession" became to have the bass-infrabass of the MK2 and the mid-high of the MK41!

At this point, I had an inspiration: why not transfer the concept of “satellites + subwoofer” to the mics? So, I bought a MK2 and, not finding on the professional market the right stuff to accomplish this project, I had to build a particular preamp-crossover-mixer system for the three mics: this quite complex unit is made up of three preamps, a second order Bessel electronic crossover and a three-way mixer. Practically every mic has its own preamp and the output of the MK2 goes into the electronic crossover and, in its turn, its output goes into the mixer, which mixes the resulting rolled-off signal into the two MK41. These ones don’t need any electronic cut to join the MK2, because they already have their natural mechanical roll-off, as I said before. The -3dB crossover point between the MK2 and the two MK41 is set at 190Hz. It is interesting to note that you need only one MK2, because it’s working only from 20Hz to 190Hz and at these frequencies, there is no stereo effect; in fact, the human ear, in open space, cannot detect the place of origin of sounds below 300Hz. Now, the only thing left is to equalise the level of the MK2 to the level of the two MK41. This operation is quite complex and you need a spectrum analyser, a hi-fi system that’s very flat in the midbass-bass-infrabass, plus a final fine-tuning “in the field”, recording and playing back concerts.

However, once you have finished, you have at your disposal a microphone-system second to none, and the result is simply astonishing! This system is working like your ears located in your head, so, to make an incomparable recording, during the rehearsal, you walk up and down the front of the stage, and when you have found the point where the sound coming from the orchestra is “in focus”, just put the “trinity” there.

Now some words about the quality of the electronics and modifications I have made to the mics. As related in the pages "Sachem pure" and "school of sound", the so-called “professional” equipment normally is not hi-end in the sound department. The same goes for the electronics inside microphones, mixers, effects generators, compressors and so on: all these appliances employ electrolytic capacitors in the signal path and if you open a big professional mixer, you’ll be impressed by the complexity of the circuits inside, which have to cater for the tooooo many “noxious" needs of the contemporary sound engineers, who unfortunately are not aware (or have just forgotten) of the existence of the mottos “the simpler, the better” or “what is missing, doesn’t damage the sound and doesn't sound itself”!

Now, speaking about the mics' technology, every condenser microphone is made up of a capsule and a body with electronic circuits, in order to feed the capsule with the right polarisation current and a preamp, to provide gain and a balanced output. So, all these mics need a “phantom" power supply: the standard one is 48V DC, but with the Schöps "bodies" (CMC3, CMC5 and CMC6) you can use different voltages and I have opted for 12V DC, because it’s easier to build an extremely pure power supply at this voltage. The current is running on the two live wires of the screened cable between mic and preamp, together with the balanced musical signal coming from the mic. The problem is that the DC of the "phantom" must be stopped before the audio-electronics inside the mic and, on the other termination, before the input of the preamp. The manufacturers of mics solve this problem with two small electrolytic capacitors and the manufacturers of professional mixers can choose between capacitors or a small transformer, made for this purpose. I personally don’t like this solution: even if the transformers avoid the use of caps, they have problems too and, in my opinion, even bigger (even if not exactly the same, see what happens in the output stage of tube amps, thanks to the transformers).

So, in microphones and in professional mixers that don’t use transformers, where a capacitance just above 300nF (0.3 μF) is required, manufacturers usually opt for electrolytic caps, due to their small physical dimensions (and cost). But, sonically speaking, electrolytic caps are the worst possible and they are located in the signal path, so you can understand their significance in the sound department and, for this reason, I did differently. I started modifying the electronics inside the "bodies" of the microphones, replacing all the electrolytic caps in the signal path, with polypropylene ones (crazy job of micro-soldering, see the photos above) and then I have built the preamp-crossover-mixer unit with the signal path electrolytic-free, and with the same electronic performances of the Sachem pure preamp, which are ... "another planet"!  I’m almost sure that, in the recording world, I’m the only one to employ in the signal path, from the mic’s capsule to the digital recorder, only four (less is impossible) very fast and respectful of the original harmonic contents Wima MKP10 series, polypropylene capacitors. Furthermore, this unit features only metal-film resistors ±15ppm/°C (very low noise) and tolerance ±0.1%. To finish, for the connection between mics and preamp unit, I use very high-quality microphone screened cables, as short as 5 metres, and for sure this is an additional benefit.

I assure you that using such equipment, every recording is a milestone in sound purity, silky mid-high and richness of original harmonics and "granitic" bass!

In the first photo above, you can see my "holy trinity" (two CMC3-MK41 at 110° and the CMC3-MK2 in the centre) and, in the two shots on the right, the original "body" of a CMC3 and, below, a modified one (note the red Wima polypropylene caps). The following two shots show the inside of the "preamp-crossover-mixer" unit, which is made to be the state-of-the art, totally wire-free. In the last two photos, on the left, you see the crossover-mixer circuit and, on the right one (where I hold a small cap in my fingers), you can note the physical difference between an electrolytic capacitor and a group of polypropylene caps, which, paralleled together, provide the same capacitance as the small electrolytic cap in my fingers: it’s quite amazing the difference in dimensions, but there is also a big difference in sound and ... price too!

 


 

                                              - electronic crossover and mixer -


 

                                      - electrolytic capacitor versus polypropylene -

 

I now want to devote some words to different methods of recording classical music or any musical or sonic event that’s performed without any amplification.

There are innumerable methods and variations: the perfect method doesn’t exist and every one is a mix of pros and cons. So, for me, the best compromise between various parameters is the binaural method, which provides a better sound-stage in dimension and depth, without phase errors, plus a natural timbre of the instruments. One of the very few limits of this method is that, for a perfect playback of the recording (in dimension of the stage, depth and localisation of the performers), you should use headphones, because in theory the left ear hasn't to hear any sound coming from the right source of sound and vice versa. With a hi-fi stereo system, you cannot respect this condition entirely, particularly with omnidirectional and dipole speakers, which emit sound not just from the front panel, but from the back and sometimes laterally too (please, don’t ask me what I think of these speakers, which are real "phase-displacers", and, just for a change, cost a fortune!).

Anyway, with serious, front-emitting, phase-correct and time-aligned speakers, you achieve an almost perfect result in dimension of the stage, with a third dimension (depth), and localization of the performers. In my opinion, this recording method is better than any other and, after all, when you listen to a concert or anything live, you employ two ears and they are more than enough, aren't they?

Nevertheless, the industrial record labels use different methods, usually (if not always) the multi-microphone method. To record an orchestra, they use dozens of mics, positioning every mic in front of two or three musicians and so on. The result is appalling and if you have a perfect hi-fi system, the resulting sound is only as large as the speakers, totally flat (no third dimension), with difficult or impossible localisation of the performers and a “harsh” sound, due to the short distance between the mics and the instruments. In fact, if you listen to a violin (or any other instrument) at 2 metres or at 15 metres, the difference in sound is huge: try it yourself, and you'll understand what I mean. It seems that these things are not enough and the final cherry on the pie is the very possible addition of electronic effects and compression.

Practically, these recordings are a “festival” of bad things and also are the best ally of analogue supporters: in fact, digital is merciless and does not mitigate a tragic recording, as analogue normally does, thanks to its higher distortion, less definition, added colour, tape-hiss and various noises!

Why do they do that? Probably because it makes manipulation of the recording easier (saving money), but it’s better that you ask them, not me. Anyway, the final result, excepting a few miracles, is disturbing and, a real musical crime!

It's also interesting to note that even the musicians got accustomed to having a lot of mics around, so that, when I record a new orchestra, they sometimes ask me why I don’t set many mics around.

In this regard, it is quite funny what happened at the end of the final rehearsal of the “Christchurch Vespers”, which was going to be a world premiere, performed by Bach Musica NZ in the Holy Trinity Cathedral. When I was almost finished setting up the mics and the stuff for the recording, Andrew Perkins, the composer, came to me and asked if I was the official recorder of the event. After my affirmative reply, he, with a dubious look, asked me if the “three mics up there” were sufficient. I replied: “are you going to hire another 20 ears for listening to your concert? Furthermore, you have to know that the “three ears" up there are much more sensitive and linear than yours and positioned in a much better listening point too”. Anyway, he made the best of a bad situation and had to accept my explanation, but my feeling was he was still sceptical.

Andrew Perkins is Kiwi, but, at that time, used to live in Melbourne (he was Tutor in the "Conservatorium of Music" in Melbourne’s University), so, when the CD was ready, I posted it to him and after a few days I received the following email:

Franco, the recording is excellent - my university supervisors thought it was stunning! Thank you so much -  Andrew

 

NOTE: In order to let everyone understand the basics, I have tried to keep topics simple and use language that is not too technical: in reality things are much more complex!

If anyone is interested in live-recording, it would be a pleasure for me to talk to him: just call or email me.